Safety device for car unloading machines



Jan. 26, 1960 M. c. ADDlcKs 2,922,624

SAFETY DEVICE FOR CAR UNLOADING MACHINES Filed Dec. 14. 1956 4 Sheets-Sheet 1 BY Q, N

Jan. 26, 1960 M. c. ADDlcKs 2,922,624

SAFETY DEVICE EoR CAR UNLOADING MACHINES Filed Deo. 14. 1956 4 Sheets-Sheet 2 7 77 j" 7 757 72 7; /ya IN VEN TOR.

MM? Bv Jan. 26, 1960 M. c. ADDlcKs 2,922,624

SAFETY DEVICE FOR CAR uNLoAnING MACHINES Filed Deo. 14. 1956 A 4 Sheets-Sheet 3 IN V EN TOR.

BY #'-v/ /40/ Jan. 26, 1960 M. c. ADDlcKs 2,922,624

SAFETY DEVICE FOR CAR UNLOADING MACHINES Filed Dec. 14. 1956 4 Sheets-Sheet 4 SAFETY DEVICE FOR CAR UNLOADING MACHINES My invention relates generally to machines for handling granular or bulk material, and more specifically, to improvements in safety devices for such machines which employ cable drawn scoops or shovels for conveying bulk material between spaced points.

More particularly, my present invention is in the nature of a safety device for a mechanically controlled power shovel machine involving a cable winding drum journalled on a drive shaft, and to the cable of which is connected a material handling shovel. The drum is operatively coupled to the drive shaft by clutch mechanism operated by a lever which is moveable in onedirection to cause engagement of the clutch mechanism to impart rotation to the drum in a cable winding direction. `Such a machine usually includes a second winding drum upon which is wound a predetermined length of chain or the like, thefree end of said chain being connected to said lever so that, when a given length of cable is wound on its respective winding drum, the chain being wound on its drum will impart movement to the lever in a direction to disengage the clutch mechanism and stop winding rotation of both drums.

An important object of my invention is the provision of a safety device which will automatically disengage the clutch to render the cable winding drum inoperative in the event that the operator or the shovel drawn by the cable becomes caught or otherwise entangled by the cable as the same is being drawn toward the winding drum.

Another object of my invention is the provision of a safety device as set forth which utilizes the power of the machine for causing disengagement of the clutch, and which eliminates the necessity for a separate source of power for its operation. To this Vend, I provide a clutch lever engaging element moveable in opposite directions between an operative position, wherein it engages the clutch actuating lever and moves the same to its clutch disengaged position, and -an inoperative position out of the range of movement of said lever, cooperating abutment elements operatively associated with the drum means and the lever engaging element, said abutment elements being relatively moveable into and out of operative engagement with each other, whereby engagement of one of said elements with the other thereof will cause the lever engaging means to be moved in a direction to shift the lever to its clutch released position, and means lying in the path of movement of and engageable by an operator or an object entangled in or caught by the pulling cable to cause said relative movement between the abutment elements into engagement with each other.

Another object of my invention is the provision of a safety device as set forth whichv may be quickly and easily installed on present machines without materially A changing the structure thereof.

The above, and still further highly important objects and advantages of my invention will become apparent from the following detailed specification, appended claims and attached drawings.

! tates Patent O 2,922,624 Patented Jan. 26, 1960 Referring to the drawings, which illustrate the invention, and in which like characters indicate like parts throughout the several views: w

Fig. l is a view partly in end elevation and partly in section, illustrating a shoveling machine utilized to unload a freight car, and incorporating my invention;

Fig. 2 is a view in plan of the shoveling machine of Fig. l and including the safety device of my invention;

Fig. 3 is a View in side elevation of the machine of Fig. 2, some parts being broken away and some parts shown in section;

Fig. 4 is an enlarged transverse section taken substantially on the line 4 4 of Fig. 3;

Fig. 5 is a View corresponding to Fig. 4 but showing a different position of some of the parts;

Fig. 6 is an enlarged fragmentary transverse section taken on the line 6 6 of Fig. 3;

Fig. 7 is an enlarged fragmentary view in side eleva tion as seen from the line 7 7 of Fig. 4, some parts being broken away and some parts shown in section;

Fig. 8 is an enlarged view in side elevation of a guide pulley and safety device actuator of my invention, some parts being broken away and some parts shown in section.

Fig. 9 is a still further enlarged view partly in section and partly in end elevation taken substantially on'the irregular line 9 9 of Fig. 8;

Fig. l0 is a fragmentary transverse section taken on the line 10 10 of Fig. 9;

Fig. ll is a view corresponding to a portion of Fig. l but showing a modified form of the safety device of my invention; and

Fig. l2 is a view in top plan of the power shovel machine of Fig. ll and the safety device thereof.

In the preferred embodiment of my invention illustrated in Figs. 1-10, the numeral 1 indicates in its entirety a power shovel machine mounted on a supporting bracket 2 above a platform 3 adjacent a freight car 4 or the like, the wheels 5 of which support the car 4 on the rails 6 of a conventional railroad track. Granular material such as grain or the like, indicated at X in Fig. l, is unloaded from the car 4 through a side opening 7 therein, and falls by gravity to a receiver 8 adjacent one of the rails 6 and below the platform 3. The machine 1 includes a winding drum 9 upon which is wound a flexible cable or the like 10 which travels over a guide pulley 11 journalled in a bracket l2 that is suitably mounted on the platform 3 adjacent the car opening 7. The cable 10 extends to the interior of the car 4 through the opening 7 and at its free end is connected to a plate like scoop or shovel 13 having -handles 14 thereon for guiding by an operator.

The power shovel machine 1 comprises a generally rectangular frame 15 including a pair of side frame members 16 and 17 and end frame members 18 and 19, all preferably made from structural steel or the like. The winding drum 9 is journalled on a rotary drive shaft 20 intermediate bearings 21 and 22 in which said drive shaft Z0 is journalled, and which bearings are rigidly mounted on the end frame members I18 and 19' respectively. The drive shaft 20 is adapted to be power driven by a suitable motor not shown and rotates in a clockwise direction with respect to Figs. 4-6, as indicated by arrows therein. The Iwinding drum 9 is driven by the shaft 26 through a high torque transfer coupling in the nature of a clutch 23 corn-A prising a driven clutch element 24 connected fast to the winding drurn 9 and a driving element 25 that is axially slidably mounted on the drive shaft 20 and keyed thereto for common rotation therewith, as indicated at 26. The

v t ment onthe side frame member 17 Aby means `ofka ,pivotK pin 2S mounted in a bracket or the like 29 welded or otherwise secured to the frame member 17. The lever 27 deiines a relatively long arm 30 which extends general-ly longitudinally of the adjacent side frame member 17, and a bifurcated relatively short arm 31, the outer end of which straddles an end portion of the driving element 25, and which is provided with shifter pins 32, one of which is shown, that are received in a circumferential channel 33 in the ldriving element 25. A coil compression spring 34 is interposed between the short arm 31 of the lever 27 and a bracket element 35 mounted on the adjacent bearing 22, and yieldingly biases the lever 27 in a direction 'to4 cause operative engagement between the clutch elements 24 and 25.

Preferably integrally formed with the winding drum 9 is a second winding drum 36 having circumferential-ly extended flanges 37 and 38 at its opposite ends. It will be noted, by reference to Figs. 2, 3, and 6, that the ange 38 is formed with diametrically opposed bosses or thickened portions 39 that are bored to provide aligned transverse passages 40 which contain friction plugs 41 that engage diametrically opposed portions of the shaft 20', see Figs. v3 and 6. Each of the friction plugs 41 is yieldingly -urged toward frictional engagement with the shaft 20 by a coil compression spring 42. The springs .24 arel interposed between their respective friction plugs 41 and a respective one of a pair of adjustment screws 43 screw threaded into the outer ends of the passages 40. The friction plugs 41 are utilized to cause the winding drums 9 and 36 to be placed under a low torque driving load when the high 'torque clutch 23 is disengaged, for a -purpose which will hereinafter be more fully described.

The lever 27 is adapted to beshifted in a direction to disengage the'high torque clutch 23 by a chain 44 which is adapted to `be wound on the second winding kdrum 36, said chain having'one end anchored to the Winding drum .ange 37, as kindicated at 4S, the other end of the'chain 44 being rigidly secured to the arm 30 of the lever'27 by an anchoring bolt or the like 46. It will be noted that thechain 44'is wound on the second winding drum 36 in the same direction as is the cable on the winding drum 9, and that, when the shovel 13 is pulled away from the shoveling machine 1 to the predetermined limit of its rear-wardmovements, the unwound portion of the chain 44 hangs in a loop between the second winding drum 36 and the Vanchoring bolt 46 on the lever arm 30. During winding movements of the drums 9 and 36, cable 10 is wound on the drum 9 whereas the chain 44 becomes wound on its respective drum 36 until the shovel 13 approaches its predetermined limit of forward movement.- At this point, all of the slack in the chain 44 is taken up, and the lever 27 is shifted, under further rotation of the drums'9 and 36, to cause disengagement of the clutch elements 24 and25, when the shovel 13 reaches its limit of forward travel.

The lever is held in its clutch released position by a latch bar 47 that is pivotally secured intermediate its ends to a mounting bracket 48 that is` welded or otherlwise secured to the side frame member 417. It will be noted that the mounting bracket 4S is bifurcated, and that the intermediate portion of the latch -bar 47 is mounted between the spaced upper ends thereof by a pivot shaft or the like 49. The outer end of the latch bar 47 is formed to provide a downwardly extending hook portion 50 thatis adapted to engage an outer surface portion 51 of the lever arm 30 to hold the clutch 23 in a disengaged condition once the same has become disengaged, and during unwinding movements of the drums 9 and 36. A latch tongue 52 is pivotally secured to the inner end of the latch bar 47 for limited swinging movements on an axis parallel'to the axis of the pivot shaft 49 and that ofthe drive shaft 20. The latch tongue 52 normally rests on a lip 53 formed on the inner end of the latch bar 47, and is adapted to be engaged by one of a plurality of circumferentiall-y spaced `lugs Stprojecting'radially "out- 4 wardly from the flange 37 of the second winding drum 36 upon rotation of the drums 9 and 36 in opposite directions. With reference to Figs. 4 and 5 it Will be seen that, when the winding drum 19 is rotated in a cable winding clockwise direction, engagement of the tongue S2 by the lugs 54 Iwill cause the outer end of the latch bar 47 to be swung upwardly to permit the lever 27 to be shifted in a direction to cause engagement of the clutch elements 24 and 25. With the lever 27 thus shifted, the hook portion 5t) will rest on the top surface of the lever arm 3) when the tongue 52 is not engaged by the lugs 54. Then, when the drums 9 and l36 have rotated sufficiently to move the shovel 13 to its-limit of forward movement, the lever 27 will be shifted -to its clutch disengaged position of Figs. 2 and 4, and the hook portion 50 of the latch bar 47 will move under action of gravity to its lever retaining position of 54. The operator then manually pulls the shovel 13 toward its limit of rearward movement, causing the drums 9 and 36 in a cable unwinding direction counter clockwise with respect of Figs. 4-6. During this -unwinding rotation, the lugs 54 engage the tongue 52 and 'sw-ing the same about its pivot axis independently lof the latch ybar 47 las indicated by dotted lines in Fig. 4. After having reached its limit of rearward movement, the shovel '13a-is manually moved forwardly a short distance to create a slack-in the cable 10 betweenthe shovel 13 and the winding drum 9. At this point, there is substantially no yloacl on the winding drums 9 and 36, and 'engagement of the friction plugs 41 with the drive Ashaft 20jis sufficient to cause the drums 9 and 36to be rotated in a cable winding direction to take up the slack in Ythe cable 10. As shown in Fig. 5, one of the lugs l'54 will engage Vthe tongue 52 during `the initial winding rotation 'of thedrums 9 and 36 to swing'the latch ba'r 47 'toits position of FiguS to release the lever 27-for shifting vmovement imparted thereto by the spring 34 toward 'engagement of the clutch 23, and the shovel 13 is then `pulled forwardly to A-move granular material X toward the opening 7 of the car 4. n

For the purpose of positively shifting the lever 27 in a direction to disengage the clutch 23, shouid an operator or any foreign object become caught or entangled by the cable 10 between the shovel 13 and the guide pulley -11, I provide novel safety mechanism'now to be described. A lever engaging element inthe nature of an elongated bar 55 extends generally transversely of the axis of the drive shaft 20 andis mounted for longitudinal sliding movements ina pair of aligned apertures 56 in the side 'frame members' 1'6 and 17. At one end, the bar 55 is formed to provide a hook-like portion 57 that is adapted to engage the outer'surface 51 of the lever rarm 39, said hooklike portion 57 being provided at its upper end with an inturned lip 58 which overlies the top surface -of the lever arm 30 to prevent disengagement between the lever arm 30 and the hook-like portion 57 upon movement of the bar 55 in a lever engaging direction. A -second lever 59 is pivotally secured to the bar S5, as indicated at 60, for a common reciprocatory movement therewith and for swinging movements independently thereof on an axis generally parallel to the axis of the drive shaft 20. Mounted onthe inner end of the lever 59 is an abutment element 61which,'under swinging movements of the lever S9'in'opposite directions, is movable into and out of the path'f `circular travel of a plurality of cooperating abutment elements in the nature of circumferentially spaced pins l62 which project axially outwardly from the flange 37 of thesecond drum 36. 'The outer end portion 63 of the second 1ever 59 extends between a pair of vertically spaced rollers 64 that are journalled on generally horizontal axes between thelegs 65 ofthe bifurcated lower end of a vertically disposed reciprocatory rod 66 that is mounted for sliding movements in a bearing element 67 welded or'otherwise anchored to a mounting plate 68 which is `b'lted'or `otherwise'rigidly secured to the side frame element 16 and which extendsy upwardly therefrom,

see Figs. 2, 4, 5 and 7. The rod 66 is yieldingly biased in a downward direction by a coil compression spring 69 interposed between the bearing element 67 and the bifurcated lower end portion of the rod 66, see Figs. 4, 5, and 7. It will be noted that the spring 69 kurges the rod 66 in a direction to swing the lever 59 about the axis of its pivot 60 to carry the abutment element 61 into the path of circular travel of Ithe abutment pins 62. At its upper end, the rod 66 is provided with an enlarged head 70 which defines a shoulder 71 that is engaged by a latch bolt 72 that is mounted for generally horizontal reciprocatory movements in a bearing element 73 weldedl or otherwise Secured to the mounting plate 68, see Fig. 7. The latch bolt 72 is yieldingly biased toward engagement with the head 70 by a coil compression spring '74 mounted in the bearing element 73. During normal operation of the machine, the latch bolt 72 supports the rod 66 and lever 59 in an inoperative position wherein the abutment element 61 is out of the path of circular travel of the cooperating abutment pins 62, as shown in Fig. 4. Means for setting the rod 66 and second lever 59 in their inoperative position comprises a reset lever 75 mounted intermediate its ends to the mounting plate 68 for swinging movements relative thereto by a pivot bolt or the like 76. The reset lever 75 is pivotally secured at its inner end to the head 70, as indicated at 77, and at its outer end is provided with a depending rope or cable 78, to the lower end of which is connected a handle element 79 that is disposed within easy reach of an operator, see Figs. l and 7.

An actuator in the nature of a generally circular barrier element 80 encompasses the pull cable 10 intermediate the guide pulley 11 and the shovel 13, and is secured to the front ends of a pair of laterally spaced parallel supporting rods 81 that are mounted for longitudinal sliding movements in tubular guide members 82 rigidly secured to opposite sides of the guide pulley supporting bracket 12, see Figs. l, 8, `and 9, said guide members extending generally in the direction of horizontal movement of the cable 10. Forward movement of the barrier element 80 is limited by a pair of adjustable stop nuts or the like 83 that are screw threaded on to the rear end of the supporting rods S1, said stop nuts engaging the rear ends of the tubular guide members 82. The supporting rods 81 are connected at their rear ends by ra cross bar 84, said cross bar and the rear end portions of the rods 81 and guide members 82 being contained in a housing 85 mounted on the rear end portion of the bracket 12. A coil tension spring 86 is connected at one end to the cross bar 84 and at its other end to the bracket 12 and yieldingly urges the supporting rods 81 and barrier element 80 in a forward direction away from the guide pulley 11. A flexible cable 87 is connected at one end to the cross bar 84 and runs over a pulley element 88 journalled in the housing 85 forwardly of the cross bar 84, and from thence extends upwardly to the mounting plate 68 on the power shovel machine 1 where it runs over a second pulley element 89, the upper end of the cable 87 being connected to the latch bolt 72 by means of a conventional coupling member 90. The ileXible cable 87 is provided with a conventional turnbuckle or the like 91, by means of which the cable 87 is maintained in a. relatively taut condition. Thus, if for any reason the barrier element 80 should be caused to move toward the pulley bracket 12, the exible cable 87 will be moved in a direction to withdraw the latch bolt 72 from engagement with the shoulder 71 of the head 70 and permit the spring 69 to cause the abutment element 61 to be moved into the path of travel of the abrutment pins 62. As above indicated, when one of the abutment pins 62 engages the abutment element 61, the lever engaging bar 55 will be caused to move in a direction from the left to the right with respect to Figs. 4 and 5 to shift the lever 27 to its clutch disengaged position. Thus, should any .portion of a persons clothing become caught disengaged position.

any portion of a persons body will cause movement of the barrier element S0 in a direction to shut off the machine, and prevent injury to such person. Likewise, if for any reason, the machine should fail to stop `at its predetermined limit of forward movement of the shovel 13, the shovel will engagejand move the barrier in a direction to stop the machine. Hence, my novelsafety device is elective not only to prevent injury to an operator, but also to prevent damage to the machine should etiher vof the above mentioned contingencies arise. Moreover, should a person standing on the platform 3 stumble or fall against the cables 10 and 87, consequent lateral displacement of the cable 87 will be sufficient to cause the latch bolt 72 to be withdrawn from engagement with the head 70 and cause stopping of the machine. In the event that the machine 1 is stopped by manipulation of the flexible cable 87, normal operation of the machine is reinitiated by manually pulling on the cable 10 or the shovel 13 away from the barrier element 80 and disengaging the person or object caught by the cable 10, and thereafter resetting the lever 59 by pulling on the reset handle 79. Thereafter, the machine may be operated as before.

In providing existingv power shovel machines of the type herein disclosed with the above described safety device, it is only necessary that the apertures 56 be made in the side frame members 16 and 17 for the bar 55, and that a pair of holes be ldrilled in the top flange of the side frame member 16 for reception of mounting bolts for the supporting plate 68. Further, the drum flange 57 is drilled for mounting of the abutment pin-s 62. Otherwise no modication of the machine is neces'- stantially identical to the drum-s 9 and 36 respectively,Y

are journalled on the drive shaft 93 and are adapted to be coupled thereto for common rotation therewith by a clutch 97 that is operated by a bell crank lever 98 similar to the lever 27. A cable 99 is wound on the drum 95 and a lever operating chain 100 is wound on the second drurn 96, the free end of the chain 100 being secured to an arm 101 of the bell crank lever '98. A coil' compression spring 102 yieldingly biases the lever 98 in a direction of shifting movement to cause engagement of the clutch elements comprising the clutch 9'7. Like the drums 9 and 36, the drums 95 and 96 are provided' with a low torque transfer coupling mechanism indicated at 103, and a latch bar 104, which may be assumed to be identical with the latch bar 47 of the machine of Figs. l-lO, is utilized to hold the lever 98 in its clutch A third drum 105 is journalled for free rotation on the drive shaft 93 and is axially slidable thereon, said third drum having wound thereon a ilexible chain 106 the free end of which is connected to the free end of the lever arm 101. Driving engagement is effected between the drums 96 and 105v by clutch mechanism comprising cooperating abutment elements 107 and 108 on the drums 96' and 105 respectively. A second bell crank lever 109 is pivotally secured intermediate its ends to the frame 92 and has one arm 110 thereof engaging the third drumv105 to move the same into and out of operative engagement with the adjacent end of the second drum 96. A coil compression spring 111 interposed between the adjacent portion of the frame'y 92 and the other arm 112 of the lever 109 yieldinglyV urges the lever 109 in a direction of shifting movement to cause engagement between the abutment elements 107 and 108. The abutment elements 107 and 108 are not..

mally held in theirinoperative positions out of engagement with eachother by a latch bar 113 pvotally secured tothe frame 92 and yieldingly biased toward engagement of thelever arm 112 by acoil compression spring 114.

With reference to Fig. 1l it will be seen that the cable 99 runs over a guidepulley 115 journalled -in a `bracket 116 secured to the vplatform 3 and it ma-ybe assumed that the free end of the cable .99 is connectedto a shovel not shown. A barrier element or actuator `in the nature of a exible rope or cable 117 is anchored at its lower end to the platform adjacent the pull cable 99 between the guide pulley 115 and the shovel, not shown, and at its upper end to the outer end of the `latch bar 113. When anyobject strikes the exible cable 117, the same will be moved in a direction to cause the latch bar to release the second lever 109 for shifting movements in a direction to cause operative engagement between the abutment element 107 and 108i Consequent rotation of the drum 105 will cause the chain 106 to become wound thereon andshift the lever 98 to its clutch disengaged position. Means for resetting the machine for normal operation includes a reset cable 118 that is connected at one `end to the arm 112 of the second lever 109 and which Vruns over a guide pulley 119 journalled on the frame 92. As shown in Fig. ll, the reset cable 118 depends from the pulley 119 and terminates in a handle element120 within easyreach of the operator.

While I have shown and described a commercial embodiment of my novel safety device as applied to a power shovel machine, and one modified form thereof, it will be understood that the same is capable of further modiiication without departure from the spirit and the scope of the invention as defined in the claims.

What I claim is:

1. In a power shovel machine comprising, rotary drive shaft means, rotary winding drum means .journalled on the rotary drive shaft means, a clutch including a driving element on said shaft means and a cooperating driven element connected to said rotary drum means, a clutch operating lever mounted for shifting movements between clutch engaged and released positions, and means yieldingly urging said lever toward a clutch engaged position; lever engaging means movable in one direction toshift said lever to a clutch released position and in the opposite direction toward an inoperative position to permit independent movement of said lever between its clutch engaged and released positions, a pair of cooperating abutment elements one thereof mounted for common rotation with one of said rotary means and one thereof connected to vsaid lever-engaging-means for common movements therewith, one ofsaid abutment elements being movable between an operative position to be engaged by the otherof said abutment elements upon rotation of said one of the rotary means and an inoperative position spaced therefrom wherein no engagement occurs between said abutment element during said rotation of said rotary means, whereby engagement of one of said abutment elements with the other thereof will cause the lever engaging means to be moved in a direction to shift said lever to its clutch released position, and means for causing said relative movement between said abutment elements.

.2. In a power shovel machine comprising, a rotary drive shaft, a rotary winding drum journalled on the shaft, a clutch including -a driving element on said shaft and a cooperating driven element connected to said drum, a clutch operating lever mounting for shifting movements between clutch engaged and released positions, and means yieldingly urging said lever toward a clutch engaged position; lever engaging means movable in one direction to shift said lever toa clutch .released position and in the opposite direction toward an inoperative position to permit independent movement of said `lever between its clutch engaged ,and released positions, a pair rof cooperating abutment elements connected one each `to said drum and said lever engaging means for common movements therewith, one of said abutment elements being movable between an operative position to be engaged by the other of said abutment elements upon rotation of said drum and an inoperative position spaced from the other of said abutment elements wherein no engagement occurs therebetween during rotation of said drum, whereby. engagementof one of said abutment elements with the other thereof will cause said lever engaging means 'to be `moved by said drum to` shift said lever to its clutch released position, and means for causing said relative movement between said abutment elements.

k,3. In a Vpower shovel machine comprising, a rotary drive shaft, rotary winding drum means journalled on the shaft, a clutch including a driving element on said shaft and a cooperating driven element connected to Said rotary drum means, a clutch operating lever mounted for shifting movements between clutch engaged and released positions, and means yieldingly urging said lever toward a clutch engaged position; lever engaging means movable in one ,direction to shift said lever toward a clutch released -position and in the opposite direction to an inoperative position to permit independent shifting of said lever between its clutch engaged and released positions, a pair of cooperating abutment elements yconnected one each to said rotary drum means and lever engaging means for common movements therewith, said abutment elements being relatively movable into and out of engagement with each other, whereby engagement of one of said abutment elements with the other thereof will cause said lever engaging means to be moved by said drum means to shift said lever to its clutch released position, means for moving said movable abutment element between its operative and inoperative positions, a lever latch mounted .for movements toward and away from latching engagement with said lever and yieldingly biased toward said engagement with said lever to hold said lever in a clutch disengaged position against bias of the urging means therefor, a latch engaging element on said drum means operative to move said latch in a lever releasing direction only during rotation of said drum means in the same direction as the direction of rotation of said drive shaft and inoperative to move said latch during rotation of the `drum in the operative direction, and a low torque friction element connecting said shaft to said drum means to maintain a predetermined driving force on said drum means when said clutch is disengaged.

4. In a power shovel machine comprising, a rotary drive shaft, winding drum means journalled on the shaft, a clutch including a driving element on said shaft and a cooperating driven element connected to said drum means, a clutch operating lever mounted for shifting movements between clutch engaged and released positions, and means yieldingly urging said lever toward a clutch engaged position; lever engaging means movable in one direction to shift said lever toward a clutch released position and in the opposite direction to an inoperative position to permit independent shifting of said lever between its clutch engaged and released positions, a pair of cooperating vabutment elements connected one each to said drum means and lever engaging means for common movements therewith, one of said abutment elements .being movable between an inoperative position wherein the abutment element of said lever engaging means is out of the path of travel of the abutment element on said drum meansand an operative position wherein the abutment element of said lever engaging means lies in the path .of travel of the abutment element on said drum means, whereby engagement of one of said abutment elements with the other thereof will cause said lever engaging means to be moved by said drum means to shift said lever to its clutch released position, and means `for moving said movable abutment element between its operative and inoperative positions.

5. In a power shovel machine comprising, a power driven rotary shaft, a winding drum journalled on the shaft, a clutch including a driving element on said shaft and a cooperating driven element connected to said drum, a clutch operating lever mounted for shifting movements between clutch engaged and released positions, and means yieldingly urging said lever toward a clutch engaged position; a lever engaging element movable in one direction to engage and shift said lever toward a clutch released position and in the opposite direction to an inoperative position out of the range of movement of said lever to permit independent shifting thereof between its clutch engaged and released positions, a pair of cooperating abutment elements one each on said drum and lever engaging element for common movements therewith, the abutment element on said lever engaging element being movable with respect thereto between an operative position in the path of travel of the abutment element on said drum and an inoperative position out of the path of travel of the abutment element on said drum, engagement of one of said abutment elements with the other thereof causing said lever engaging element to be moved by said drum to engage and shift said lever to its Iclutch released position, and means for moving said movable abutment element between its operative and inoperative positions.

6. The structure defined in claim in which said lever engaging element is mounted for movements in opposite directions generally parallel to the direction of movement of the portion of said lever engaged thereby between its lever engaging operative position and said inoperative position, said lever engaging element in its inoperative position being disposed beyond the limit of movement of said lever towardV its operative clutch engaged position, the abutment element carried by said lever engaging element being mounted thereon for movements transversely of the direction of movement of said lever engaging element.

7. In a power shovel machine comprising, a power driven rotary shaft, a rotary winding drum journalled on the shaft, a clutch including a driving element on said shaft and a cooperating driven element connected to said drum, a clutch operating lever mounted for shifting movements between clutch engaged and released positions, and means yieldingly urging said lever toward a clutch engaged position; a lever engaging element movable in one direction to engage and shift said lever toward a clutch released position and in the opposite direction to an inoperative position out of the range of movement of said lever to permit independent shifting of said lever between its clutch engaged and released positions, a second lever pivotally secured to said lever engaging element `for swinging movements relative to said lever engaging element, a4 second abutment element on said second lever engageable with said iirst mentioned abutment element upon movement of said lever engaging element to its said inoperative position and upon swinging movement of said second lever in one direction, yielding means urging said second lever in said one direction of swinging movement, latch means releasably locking said second lever against said swinging movement in said one direction, and a manually operated release member for said latch means.

8. In a power shovel machine comprising, power driven rotary shaft means, rotary winding drum means journalled on the shaft means, a clutch including a driving element on said shaft means and a cooperating driven element connected to said rotary drum means, a clutch operating lever mounted for shifting movements between clutch engaged and released positions, and means yieldingly urging said lever toward a clutch engaged position; lever engaging means movable in one direction to shift said lever to a clutch released position and in the opposite direction toward an inoperative position to permit independent movement of said lever between its yclutch engaged and released positions, a pair of cooperating abutment elements one thereof mounted for common rotation with one of said yrotary `means and the otherA thereof mounted on said lever engaging means for com-- mon movements therewith, one of said abutmentelements being movable with respect to the means on which it is mounted and in a direction toward engagement with the other of said abutment elements, whereby to cause said lever engaging means to be moved in a direction to shift saidlever to its clutch released position responsive to rotation of one of said rotary means, yielding means urging one of the abutment elements toward the other thereof, a movable latch element releasably locking said one of the abutment elements against movement toward the other one of said abutment elements, and an elongated latch release member connected at one end to said latch element and extending to a point remote from the machine and adjacent the path of travel of a load pulled by said machine and engageable with said load to be moved thereby in a direction to impart releasing movement to said latch element, whereby said one of the abutment elements is moved toward engagement with the other of said abutment elements by said yielding means.

9. In a power shovel machine comprising, a power driven rotary shaft, a winding drum journalled on the shaft, a clutch including a driving element on said shaft and a cooperating driven element connected to said drum, a clutch operating lever mounted for shifting movements between clutch engaged and released positions, and means yieldingly urging said lever toward a clutch engaged position; a lever engaging element movable in one direction to engage and shift said lever toward a clutch released position and in the opposite direction to an inoperative position out of the range of movementof said lever to permit independent shifting thereof between its clutch engaged and released position, a pair of cooperating abutment elements one each on said drum and said lever engaging element for common movement therewith, the abutment element on said lever engaging element being movable with respect thereto between an operative position in the path of travel of the abutment element on said drum and an inoperative position out of the path of travel of the abutment element on said drum, engagement of one of said abutment elements with the other thereof causing said lever engaging element to be moved by said drum to engage and shift said lever to its clutch released position, yielding means urging one of the abutment elements toward the other thereof, a movable latch element releasably locking said one of the abutment elements against said movement toward its operative position, and an elongated latch release member connected at one end to said latch element, the opposite end of said release member being disposed at a point remote from the machine and adjacent the path of travel of a load pulled by said machine and engageable with said load to be moved thereby in a direction to impart releasing movement to said latch element, whereby said one of the abutment elements is caused to move toward engagement with the other of said abutment elements by said yielding means.

10. In a power shovel machine comprising, a power driven rotary shaft, a winding drum journalled on the shaft, a clutch including a driving element on said shaft and a cooperating driven element connected to said drum, a clutch operating lever mounted for shifting movements between clutch engaged and released positions, and means yieldingly urging said lever toward a clutch engaged position; a lever engaging element movable in one direction to engage and shift said lever toward a clutch released position and in the opposite direction to an inoperative position out of the range of movement of said lever to permit independent shifting thereof between its clutch engaged and released positions, an abutment element mounted for common movements with said drum, a second abutment element, a second lever pivotally secured to said lever engaging element and mounting said second abutment element for common movements with said"lever engaging element andfor independent movement relative 'thereto toward and away from said trst mentioned abutment e1`ement,-yielding means urging saidI second lever in adirectionto move its respective abutment element toward the abutment element carried by said drum means, a 4latch releasably locking said second lever against vmovement in said direction, and an-elongated latch release member connected at one end to said latch, the opposite end` of said release member being disposed at a point remote from the machine and adjacent the path of travel of a load pulled by said machine and engageable with said load to be moved thereby in a direction to impart releasing movement to said latch release member, whereby said one ofthe abutment'elements is moved toward engagement with the other of sadabutment elements by said yielding means.

'11.In a power shovel machine comprising, a rotary drive shaft, rotary Winding drum means journalled Aon the shaft, a clutch including a driving element on said shaft and a cooperating driven element connected to said rotaryidrum means, a clutch operating lever mounted for shifting movements between clutch engaged and released positions, and means yieldingly urging said lever toward a clutch engaged position; lever engaging means movable in one direction to shift Asaid lever to a clutch released position and in the lopposite vdirection toward an inoperative position to permit independent movement of said lever between its clutch engaged and released positions, apair of cooperating abutment elements mounted one each on said drum means `and lever engaging means for common movements therewith, one of said abutment elements being .movable ,relative to the means on which `it is mounted and in avdirection :toward engagement with the other of said abutment elements, whereby to cause said lever engaging means to be moved in a directionto shift said'lever to its clutch released position responsive to rotation of oneof -said rotary means, yielding means urging oneof `the kabutment elements toward the other thereof, a latch releasably locking said one of the abutment elements against said movement toward'the other abutment element, a bracket 'remote from said drum means, an 'actuator mounted on said bracket for movements in opposite directions parallel to and in the path of a load pulled by said'machine, yieldiing means urging said actuator in one direction o f its movement, andan elongated latch release cable connected at one end to said latch and at its opposite-end to said actuator, said release cable being moved by said load when the same is pulled into engagement with said actuator and against bias yof said last mentioned yielding means to impart releasing movement to said latch element, whereby saidone ofthe abutment elementsis caused to move toward engagement with the other of said abutment elements by the yielding means associated with said one of the abutment elements.

References Cited in the tile of this patent UNTED STATES PATENTS Y 278,993 Metcalf June 5, 1883 `317,083 Bradford May 5, 1885 398,502 Dyblie et al. Feb. 26, 1889 2,470,059 Watson et al. s May 10, 1949 2,705,126 Addicks Mar. 29, 1-955 FOREIGN PATENTS 704,470 Great Britain Feb. 24, 1954 

